TRENTON, N.J.(CBSNewYork) — It may not be widely known but breast density can make it more difficult for mammograms to detect breast cancer.

As CBS 2’s Kristine Johnson reported up to 50 percent of tumors can be missed in women with the densest tissue.

Now, a new law in New Jersey seeks to raise awareness about the issue but some say that it could cause confusion instead.

Laurie Scofield was shocked to hear her advanced breast cancer diagnosis. She had a lump in her breast but it didn’t show up on her mammogram and doctors assured her that it was just a cyst.

“My doctor told me not to worry about it. I didn’t,” she said.

Four months later the lump became uncomfortable and Scofield had an ultrasound done. The lump turned out to be cancer.

“I couldn’t believe it,” she said, “I was in disbelief.”

Scofield has very dense breast tissue which can make it difficult to detect tumors. In women with the densest tissue mammograms can miss cancer as often as half of the time.

After undergoing 9 months of treatment Scofield became an activist and pushed for a New Jersey Law that would require doctors to notify women if they have dense breasts.

However, Scofield said that the law that was passed could do more harm than good. Now, all women who have a mammogram will receive a letter informing them that they may have dense breast tissue even though 40 percent of women actually do.

Some say the one size fits all approach could alarm woman unnecessarily.

“It makes absolutely no sense,” Radiologist, Dr. Lisa Weinstock said, “It’s going to put them in a panic as to whether they do or don’t and they may insist on imaging that they don’t need.”

Dr. Sharon Mass of the American College of Obstetricians and Gynecologists, lobbied against alerting only women with the densest tissue.

“It can result in unnecessary biopsies and interventions for many more women which has been shown to have long-term psychological harm to those women,” Dr. Mass said.

The group succeeded in changing the legislation so that all women are told that they have dense breasts, a move that Scofield opposed.

“That’s gonna make everyone in the state anxious,” she said, “They’re still not gonna know whether or not they have the condition.”

The letter advises women to discuss their density and other risk factors with their doctor. Some doctors have these discussions, many do not.